This project involves construction of a new gravity trunk sewer system between School Street and Nimitz Hwy, along Waiakamilo Rd, Houghtailing St., and several side streets (see attached project map).
The extent of work is as follows:
- 6,000 linear feet of new 42-inch and 54-inchdiameter gravity sewer pipelines;
- 500 linear feet of new 8-inch and 12-inch diametergravity sewer pipelines;
- 23 new sewer manholes;
- 16 microtunneling shafts;
- 19 temporary sewer bypass systems;
- 4 water line relocations;
- 3 gas line relocations;
- Various other site work and restorations.
Open-cut trench construction will be used to install the 8-inch and 12-inch diameter gravity sewer pipelines and the various utility relocations that are necessary to constructing the new trunk sewer system.
The new 42-inch and 54-inch diameter pipelines will be installed using a pipeline construction method called microtunneling. Microtunneling only requires excavations, (a.k.a. microtunneling shafts) at manhole locations. A microtunneling machine with the same diameter as the new sewer pipe will bore a tunnel between the microtunneling shafts while the new pipe is simultaneously put into place behind it.